In Patent Documents 1-3, the present applicants proposed a mono-axial waterproof connector used mainly for providing through-connections for outdoor cabling and the like. FIGS. 19-22 show the construction of the waterproof connector 1 described in Patent Document 1. This waterproof connector 1 is adapted for use as a connector in situations where the cables 12, 13 are cut to the desired length and components are attached to their terminals at a work location.
The illustrated waterproof connector 1 is configured either as a plug 2 that has a male terminal 21, or as a receptacle 3 that has a female terminal 31. When two connectors are interengaged, two terminals become electrically connected. On the outside, the plug 2 and receptacle 3 are substantially cylindrical in shape and are attached to the terminals of the cables 12, 13 in line with their respective axial centers. The cross-sectional structures of the plug 2 and receptacle 3 are generally similar except for the peripheral portions of the terminals 21, 31. Namely, the plug 2 and receptacle 3 are respectively equipped with terminal mold portions 22, 32, which cover a male terminal 21 or a female terminal 31; substantially cylindrical watertight sleeves 26, 36, which cover a range extending from the terminal mold portions 22, 32 to the outer casings 122, 132 of the cables 12, 13, and fastening members 27, 37, which cover substantially the entire length of the watertight sleeves 26, 36 and are interfitted or threadably engaged with the terminal mold portions 22, 32.
The terminal mold portions 22, 32 are formed integrally using the so-called insert molding (over-molding) technique, in which a tubular female terminal 31 or a rod-like male terminal 21 made up of an electrically conductive metal is placed in a mold and subjected to injection molding using a synthetic rubber-type material. The terminal mold portions 22, 32 are formed such that the distal end portions 23, 33, which cover the terminals 21, 31, are made thinner, and the diameter widens from the central portion towards the forward end portion. The rearward end portions of the terminals 21, 31 pass through the distal end portions 23, 33 of the terminal mold portions 22, 32 and are slightly exposed at the rearward end of the terminal mold portions 22, 32. The conductors 121, 131 exposed by removing the outer casings 122, 132 of the cables 12, 13 are inserted into the exposed portions and secured by crimping.
It should be noted that when the construction of the waterproof connector 1 is described in the present specification, the side of the plug 2 and receptacle 3 used for engagement with its counterpart is referred to as the “forward end”, whereas the opposite side (the side connected to the cables 12, 13) is referred to as the “rearward end”.
The forward end portion of the terminal mold portions 22, 32 extends forward to surround the terminals 21, 31, forming a mating recess portion 221 (provided in the plug 2) and a mating projection portion 321 (provided in the receptacle 3) that are mutually interfittable. Ridge members 222, 322 with sawtooth cross-sections are formed on the mating faces of the mating recess portion 221 and mating projection portion 321 in order to increase the strength of mutual interfitment and water-tightness.
The watertight sleeves 26, 36, which are made up of a synthetic rubber-type material of superior elasticity, are mounted from the outer casings 122, 132 of the cables 12, 13 all the way to the distal end portions 23, 33 of the terminal mold portions 22, 32. The inner circumferential surface of the rearward end of the watertight sleeves 26, 36, which is formed to have an undulating cross-section, surrounds the outer casings 122, 132 of the cable 12 in a watertight manner. In addition, mounting grooves 262, 362 are formed in the inner circumferential surface of the forward end of the watertight sleeves 26, 36. These mounting grooves 262, 362 are interfitted with the mounting step portions 231, 331 formed on the outer circumferential surface of the distal end portions 23, 33 of the terminal mold portions 22, 32, thereby ensuring the water-tightness of the interface. The watertight sleeves 26, 3626 are formed such that their wall thickness increases and their outside diameter expands from the rearward end towards the forward end.
The fastening members 27, 37 are formed from a synthetic resin-based material of a rigidity that is higher than that of the synthetic rubber-based material used to form the watertight sleeves 26, 36. The fastening members 27, 37 are mounted throughout the entire length of the watertight sleeves 26, 36 and substantially half of the rearward end of the terminal mold portions 22, 32, thereby protecting the same. Threadably interengaged tapered threaded portions 251, 252, 351, and 352 are provided on the inner circumferential surface of the fastening members 27, 37 and on the outer circumferential surface of the terminal mold portions 22, 32, with the threaded engagement surface sealed in a watertight manner by tightening the fastening members 27, 37. In addition, the inner circumferential surface of the fastening members 27, 37 is formed to have a diameter that becomes narrower from the forward end to the rearward end, with this inner circumferential surface clamping the outer circumferential surface of the watertight sleeves 26, 36 with sufficient force.
Furthermore, locking projection portions 241, 341 are formed in the forward end portion of the fastening members 27, 37. When the fastening members 27, 37 are threadably engaged, these locking projection portions 241, 341 are engaged with the locking recess portions 242, 342 formed on the outer circumferential surface of the terminal mold portions 22, 32, thereby preventing the engagement from being easily loosened.
In this way, along with reliably maintaining intimate contact at the interface of the watertight sleeves 26, 36 and terminal mold portions 22, 32 as well as at the interface of the watertight sleeves 26, 36 and outer casings 122, 132 of the cables, the fastening members 27, 37 maintain a sufficient clamping force based on the rigidity of the fastening members 27, 37 themselves and resist external forces such as impact or bending stresses. In such a configuration, stable waterproofing performance can be obtained over an extended period of time.
FIG. 23 illustrates a waterproof connector 1 disclosed as another embodiment in Patent Document 1. In this waterproof connector 1, fastening members 27, 37 provided in the plug 2 and receptacle 3 are respectively provided with pawl portions 4 and a pawl-receiving portion 5. The pawl portions 4 extend from the fastening member 37 provided in the receptacle 3 towards the terminal mold portion 32 and are formed to be resiliently deformable. In addition, the pawl-receiving portion 5, which receives the pawl portions 4, is formed on the exterior of the fastening member 27 provided in the plug 2. When the plug 2 is interfitted with the receptacle 3, these pawl portions 4 and pawl-receiving portion 5 are interengaged and resist separation of the plug 2 from the receptacle 3. As a result, a stable joined state and waterproofing performance can be ensured for an extended period of time.
In addition, Patent Document 4 discloses a configuration wherein, in a connector made up of a plug and a socket (receptacle) as described above, locking protuberances protruding from one side (corresponding to the pawl portions 4 in the waterproof connector 1 of FIG. 23) are engaged with an engagement portion on the other side (corresponding to the pawl-receiving portion 5 in the same figure). This engagement portion is provided with a skirt portion covering the forward end portion of the locking protuberances inserted into the engagement portion. This skirt portion prevents the engaged locking protuberances from disengagement due to inadvertent fingertip manipulation or to the action of external forces and is designed to prevent disengagement unless special tools are used. However, the above-mentioned document does not specifically describe the internal structure of the connector and does not clarify the terminal molding and assembly methods used.